A significant number of conventional golf balls are made by molding a cover about a core having a typical core diameter of about 1½ inches. One form of golf ball construction includes balls having a solid core. Solid core golf balls are referred to generally as “two-piece” golf balls.
The core of a two-piece golf ball is based upon rubber compositions which are formulated to provide high hardness, high compressive strength, durability, and excellent rebound properties. Such rubber core formulations provide resiliency to the resulting golf ball which optimizes initial velocity at impact and promotes long flight distance qualities.
Polybutadiene elastomers are commonly used for the rubber component of a core and are cross linked by chemical cross-linking agents to increase the hardness while maintaining good resiliency. It is well known within the art in the manufacturing processes and formulations for which conventional two-piece golf ball cores may be manufactured. One representative patent includes U.S. Pat. No. 5,508,350 which is incorporated herein by reference. Despite advances within the art, such as represented by the above referenced patent, there remains room for improvement and variation in the art directed to core constructions which provide high initial velocity to the resulting golf ball while maintaining the durability of the core. Should the integrity of the core be compromised by cracking or other core damage, the ball will suffer a loss of initial velocity. The degradation in ball performance may be gradual and may not be immediately apparent to the user. Accordingly, cores which retain their durability will extend the useful performance life of the golf ball.
It is also known in the art to provide golf balls having a plurality of dimples or surface indentations which are more or less evenly distributed over the surface of the ball. It is well known that the dimple pattern improves and affects the flight characteristics of the ball in that the dimple shapes may vary in number and configurations.
It is further known that the dimple edges present on the face of a golf ball may have a detrimental effect on soft putting strokes. As mentioned in U.S. Pat. No. 5,662,530 which is incorporated herein by reference, a putter which contacts a dimple off center i.e., partially on a dimple edge adjacent a land area, the force of the putting stroke is not transmitted to the center of the ball. The resulting putted ball leaves the putter head at a tangent. The putting force also produces a moment about the center of the ball resulting in a small amount of spin. A small 5 degree off set from a line through the center of the ball in the direction of the putting stroke can result in a misdirection on a 4 foot putt to 2.1 inches which is sufficient to miss the cup. The missed distance from the cup is, of course, greater as the distance of the putt increases.
Accordingly, there is room for variation and improvement in the dimple pattern of a golf ball so as to minimize the amount of off-center dimple contact between the ball and the putter head while maintaining an overall dimple pattern which has good flight performance characteristics for optimized distance.